On 10/07/2012 08:30:06 AM, Alexander Graf wrote:
On 07.10.2012, at 15:26, Avi Kivity wrote:
> The downside of this generic approach is that it prepares suprises
down
> the road. The alternative approach, of adding a new KVM_EXIT_RESET,
> avoids this minefield, but requires ABI changes every time we want
to
> emulate something in userspace. Can you provide a critique of this
> alternate approach?
Yeah, it doesn't scale as well. The SPR read/write give us all
information we need to emulate other registers too, like the magical
"read this SPR and automatically get the interrupt vector from the
MPIC and ack the interrupt along the way" register we have on e500.
That's not actually how the register works in hardware (though it may
be a reasonable way to emulate it with a userspace mpic). The
interrupt is acknowledged when the core branches to the interrupt
vector. The register itself is just storage that gets filled when that
happens.
-Scott
--
To unsubscribe from this list: send the line "unsubscribe kvm" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
